Esters of 2.3-amino-naphthoic acid and aprocess of preparing them



Patented Apr. 18, 1933 UNITED-STATES WARE P T}: NT-foF F IC 1 i LUDWIGSANDER, or .Imnxron'r.ounnnmnmaocnsr; GERMANY, nssienoa' TO GENERAL'ANILINEI WORKS, mo, onmnw YoR N. A CORPORATION? or DELA-JV a ESTERS0E23-AMINO-NAPHTHOICACIDAND A PROCESS, orgrmirnnine THEM m; matinApplication "filedjuly 1,1929, SeriaLNo. sta ssaanam cer an iin 14 1928.

The present inventionrelates to esters of 1 2.3-amino nap'hthoio acidand to a process of preparingthesame; more particularly it relates to a"process of preparing compounds of the'following general formula whereinR standsfor an acyclic or isocyclic residue.

Hitherto esters ofthe 2.3 amino na p hthoicacid haveombeen"obtainedaccording to the usual method of esteri'ficationby means ofalcohol and mineral ac ds wh ch esterification, however, 1S lna verysurprisingmanner much more difficult to carry out and'less completethan, for instance', the esterification of the analogous anthranilicacid and .its derivatives.

Now I have found the esters of 2.3- amino-naphthoic acid, which are ofgreat a value for ithe production 'of'dyestufi's, are

vvery, easily, obtained by "first converting: the 2.3:amino-naphthoic--acid by means 10f chlorocarbonic; acid esterv or ehosgenev (for Vinstance according to the process described in; French 'Patent ;No.603,970.) into 2.3- naphthisatoic ,anhydride and then causing 'toactupon the latter an alcoholor a phenol while adding an acidbinding agent,such as potassium carbonate, sodium acetate, pyridine or the like. TheCO -group of the nanhthisatoic anhydride attached to the NH- group isthereby'split ofi? as carbonic acid.

The following equation illustrates the course of the reaction:

' equivalent of the acid bindin-g agent.

thisatoic anhydride only-a fraction of'an The 2.3-amino-naphthoic estersare-yellow compounds, soluble inorganic solvents and in dilute mineralacids, insoluble in aqueous alkalies Theyi are diazotizable and,therefore, valuable components for azo' dyestuffs.

The following examples 'serveto illustrate 1 my invention but are'notintended to limitiit thereto/the parts being by weight: a v (1) 500parts of2L3-naphthisatoic anhy dride are heated to-boiling-in areflu'xappa I ratus with about 500" parts of finely pulverized potassiumcarbonate and 5000 parts of methyl alcohol until the naphthisatoicanhydride has entirely dissolved and the evolution of carbonic acidceases. 1 1 a f I The methyl alcohol is thenjelxpelled, the residue isstirred withwat'e'r, filtered by suct'ion, Washed, and if desired,recrystallized from alcohol orlbenzene or urified in known I manner byway of the hy rochloride'l The yield amounts to 7 1 per centofthe-theoreticalj v The 2.3-amino-naphthoic acid methylester thus obtained-whichhas the formula C. to.

ish-yellow needles --melting3 at 104 105 36;. a i

By, substituting in Example l ethyl alcohol tor methyl alcohol, there'isobtained the ethyl ester, of 2.3-amino-naphthoio acid melting at 117 to118 (1,

. In an analogous manner there may also be obtained other esters fromthe corresponding alcohols, such as,for instancefisopropylester (meltingat C.) butylester (in-the form of yellow needlesmelting at C. to 101(1), isobutylester (melting at 99C; to 100 C.)fand benzylester meltingat 105 C. t01'069 1, 1

crystallizes from alcohol in brilliant green- (3) By replacing inExamples 1 and 2 potassium carbonate by the equal quantity of anhydroussodium acetate, sodium carbonate or potassium bicarbonate, the esters ofthe 2.3-amino-naphthoic acid are obtained in the same easy manner. Theremay also be used mixtures of acid binding agents. The products areworked up in the manner described in Example 1.

(4) 500 parts of 2: 3-naphthisatoic anhydride are heated to boiling in areflux apparatus together with parts of finely pulverized potassiumcarbonate and 5000 parts of methyl alcohol until the 2.3-naphthisatoicanhydride has entirely dissolved and the evolution of carbonic acidceases.

The working up is the same as described in Example 1. cent of thetheoretical.

(5) 500 parts of 2.3-naphthisatoic anhydride are heated to 80 (1, whilevigorously stirring, with 3000 parts of anhydrous glycol and 300 partsof finely pulverized potassium carbonate until the naphthisatoicanhydride has entirely dissolved and the evolution of carbonic acidceases. The whole is then diluted with water, whereby the potassiumcarbonate dissolves and the ester is precipitated as a quicklysolidifying oil. After it has become entirely solid the ester isfiltered with suction, dissolved in dilute hydrochloric acid and againprecipitated with dilute caustic soda solution or other bases. The yieldamounts to per cent of the theoretical. The 2.3-aminonaphthoic-glycoLmono-ester which has the formula NHa COOCHLCHZ OHrecrystallizes from methyl alcohol in clusters of fine yellow needlesmelting at 102 C. to 103 C.

From the mother liquor of the crude ester the excess of glycol can berecovered in the usual manner.

(6) By replacing in Example 5 the potassium carbonate by the equalquantity of pyridine the ester is obtained in the same smooth reaction.The ester is isolated as indicated in Example 5.

(7 500 parts of 2.3-naphthisatoic anhydride, 3000 parts of phenol and300 parts of potassium carbonate are heated, while vigorously stirring,to 0 C. to C. until the evolution of carbonic acid ceases. The reactionproduct is stirred with water whereby the ester first separates as anoil which, however, soon solidifies. It is filtered by suction, washeddried and, if desired, recrystallized from benzene. The 2.3-amino- Theyield amounts to 71 pernaphthoic phenyl ester which has the formula:

crystallizes from benzene in yellow laminae melting at 135 C. From theaqueous mother liquors the excess of phenol can be recovered in theusual manner.

I claim:

1. Process which comprises causing 2.3- naphthisatoic anhydride to reactwith a compound of the following general formula:

ROH

wherein R stands for an aliphatic or a phenyl-or benzyl-residue in thepresence of an acid binding agent while heating at moderate temperature.

2. Process which comprises causing 2.3- naphthisatoic anhydride to reactwith an aliphatic alcohol in the presence of alkali carbonate whileheating at moderate temperature.

3. Process which comprises causing 2.3- naphthisatoic anhydride to reactwith methyl alcohol in the presence of potassium carbonate while heatingat a temperature up to about the boiling point of methyl alcohol.

1. As new products compounds of the following general formula OOOR OH:CO 0.01!

CHI

being a yellow compound, melting at C, soluble in organic solvents andin dilute mineral acids, insoluble in aqueous alkalies and forming adiazonium compound when treated with nitrite and an acid.

6. As a new product, the compound of the following formula:

ooo.c11,.oH,oH

being a yellow compound, melting at 102 C.

to 103 (3., soluble in organic solvents and in dilute mineral acids,insoluble in aqueous a1- kalies and forming a. diazonium compound whentreated with nitrite and an acid.

7. As a new product, the compound of the following formula;

being a yellow compound, meltinget 0., soluble in organic solvents andin dilute mineral acids, insoluble in aqueous alkalies and forming adia'zonium compound whentreated with nitrite and an acid.

In testimony whereof, I aflix my signature. v

LUDWIG SANDER.

